A pressure contact type semiconductor device generally includes a structure in which a semiconductor element disposed in an insulating frame is interposed between and hermetically sealed in part by upper and lower electrode blocks. Internal electrical contact is maintained by applying an external pressing force from outside the upper and lower electrode blocks. Furthermore, the pressure contact type semiconductor device achieves an improvement of power density and high reliability operating at a high voltage and a high current by double-sided heat radiation.
If the semiconductor element inside the pressure contact type semiconductor device is destroyed, part of the pressure contact type semiconductor device can sometimes be short-circuited without damaging the remainder of the semiconductor device. Therefore, even after the semiconductor element is destroyed, it is possible to operate a system including the semiconductor device without stopping the system immediately by using a plurality of the pressure contact type semiconductor devices connected in series. Thus, a redundant design can easily be used with pressure contact type semiconductor devices.
However, if an overload state continues in the destroyed semiconductor element, melting of the semiconductor element can occur due to a substantial increase in temperature, and thereby an internal pressure may rise and lead to an explosion. If the explosion occurs, pieces of the semiconductor device are scattered in multiple directions, and circuits or cooling devices in the vicinity of the semiconductor device can become damaged, and thereby the whole system may become inoperable.